A composition obtained by blending a crosslinking agent and carbon nanotubes (hereinafter frequently referred to as “CNTs”) into hydrogenated carboxylated nitrile rubber that has heat, ozone, chemical, and oil resistances is conventionally known, as described for example in Patent Literature 1 (PTL 1). A vulcanized material obtained by vulcanizing a composition described in Patent Literature 1 has higher tensile strength and elastic modulus while maintaining elongation at break and strain characteristics.
CNTs are now attracting attention as carbon materials that effectively improve electrical conductivity and mechanical characteristics. The rubber composition containing a rubber component and carbon nanotubes are thus attracting attention as a material having superior electrical conductivity and mechanical characteristics.